Many people wear glasses to correct a variety of optical issues (e.g., near-sightedness, far-sightedness, astigmatism, etc.). Wearers of glasses tend to have few options when selecting a type of sunglass. Some choose to buy prescription sunglasses, clip-on sunglasses, or may choose to wear standard sunglasses rather than their prescription glasses. Others may choose to wear photochromatic glasses such as transitional lenses. These may allow a person to wear a single pair of glasses in both light and dark places, without the need to switch to sunglasses. The typical transitional lens works through a chemical reaction to ultraviolet (UV) radiation. In some cases, transitional lenses may work when exposed to visible light, which may work when a person is in a location where UV light may be blocked such as a vehicle.